Biofilms: Biofilms: understanding understanding physiology for - - PowerPoint PPT Presentation
Biofilms: Biofilms: understanding understanding physiology for developing physiology for developing new therapeutic strategies new therapeutic strategies Mohammad Shahrooei Mohammad Shahrooei & & Professor Johan Van Eldere
Mohammad Shahrooei Mohammad Shahrooei & & Professor Johan Van Eldere Professor Johan Van Eldere October 5 October 5th
th, 2012
, 2012
Structured communities of bacterial cells enclosed in a self‐produced polymeric matrix and adherent to an inert or a living surface.
A biofilm is like a tiny city in which microbial cells form towers. The "streets“ between the towers are fluid‐filled channels that bring in nutrients, oxygen and
(Quorum Sensing)
USA and EU annually
prostheses and heart valves
and coagulase‐negative staphylococci
(CoNS), in particular, S. epidermidis, have emerged as major
nosocomial pathogens associated with DRI, due to the facts that:
Staphylococcus spp.
, and extracellular DNA
‐1, 6‐linked N‐ acetylglucosamine
Schematic procedure of PIA synthesis (a) and the gene arrangement in the ica
Staphylococcus aureus)
remove the implant, fight the infection with antibiotics, and replace the implant, a risky, costly and stressful procedure
expression is limited to surface‐exposed area and agr mutants occur naturally in deeper layers
‐ Current and finished clinical vaccine trials using active immunization ‐ Merck V710 vaccine ‐ StaphVax developed by Nabi ‐ EpiVAX™ ‐ Vaccines in pre‐clinical development using active immunization ‐ Alpha‐toxin ‐ Panton‐Valentine leukocidin (PVL) ‐ PentaStaph (Nabi) ‐ Multi‐component adhesin vaccine ‐ Poly‐N‐acetylglucosamine (PNAG) ‐ Als3p (Novadigm): ‐ Iron‐regulated proteins (Syntiron/Sanofi Pasteur)
‐ Passive immunization strategies in clinical trials ‐ Altastaph from individual treated with Nabi’s StaphVax ‐ Clumping factor (ClfA) targeted antibodies ‐ Aurograb ‐ Pagibaximab ‐ Passive immunization strategies in pre‐clinical development ‐ Alpha toxin ‐ PVL ‐ Superantigens
peptide;
TM, transmembrane helix; PBD, peptidoglycanbinding domain; CBD, choline‐binding domains
Ideal anti‐biofilm vaccine targets are surface components that were conserved across the species, in particular those which are highly expressed in the bloodstream and in biofilms, with a possible role in biofilm formation or an essential function
number of antigenic determinants and the importance of the protein family, to which the candidate protein belongs, in S. epidermidis biofilm formation and pathogenesis
in E. coli and polyclonal anti‐Ses antibodies were raised against them and specific anti‐Ses antibodies were purified using antigen‐ affinity purification
assay
(Primary attachment) (Overnight biofilm formation)
Pre‐immune (□) Post‐immune (■)
Primary attachment Specific and dose-dependent effect Effect on 1-day established biofilms
Subcutaneous catheter (SC) rat model Jugular vein catheterized (JVC) mouse model
immunization)
Passive immunization Active immunization
60.42-fold 20-fold
24 h after the implantation, JVC mice were inoculated with 1.0E+8 CFU 10b pre‐ incubated with pre‐immune or αSesC‐IgG’s. 5 days after inoculation, the number of bacteria colonizing the catheter, organs or in blood stream was quantified by CFU
In vitro neutralization In vivo
Semi‐quantitative microtiter plate In vitro opsonophagocytosis assay
24 h after the implantation, JVC mice were inoculated with 1.0E+7 CFU S. aureus via the catheter lumen, 5 days after inoculation, the number of bacteria colonizing the catheter, organs or in blood stream was quantified by CFU counting. The error bars indicate the standard errors of the mean. * P<0.05; ** P<0.01; *** P<0.001
Effect of pre‐incubation with pre‐immune or αSesC‐IgG’s on S. aureus 8325‐4 strain and its sesC‐positive transformant
Transformation with sesC changes the phenotype of biofilm formation of PIA‐ dependent biofilm‐forming strains
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Transformation with sesC changes the phenotype of biofilm formation of PIA‐ dependent biofilm‐forming strains
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Transforamtion with sesC changes the phenotype of biofilm formation of PIA‐ dependent biofilm‐forming strains
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Transformation with sesC changes the phenotype of biofilm formation of PIA‐ dependent biofilm‐forming strains
* * * *
Transformation with sesC changes the phenotype of biofilm formation of PIA‐ dependent biofilm‐forming strains
* *
Transformation with sesC changes the phenotype of biofilm formation of PIA‐ dependent biofilm‐forming strains
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